Hi, im making a list of parts for a computer that will be made for me and this one puzzled me... The Asus 7800GTX... It says its an asus nVidia 7800GT.. I don't get it.. is it a graphic card or a mother board?? Sorry if this is a stupid question, and if it is, then explaining will be easy :P And it costs 600 dollers.. is that a fair price?? (Canadian Currency)

Or here is my list of possible cards:
Asus - 7800 GTX $600
850XT $549

Radeon - x850 Crossfire 389$
x850 Pro $319

Since im low on the budget, how about the x850 Crossfire.. is that any good?